[lldb] [test] Mark failing tests XFAIL on NetBSD

Add a convenience 'expectedFailureNetBSD' decorator and mark all tests
currently failing on NetBSD with it.  Also skip a few tests that hang
the test suite.  This should establish a baseline for the test suite
and get us closer to enabling tests on buildbot.  This will help us
catch regressions while we still have a lot of work to do to get tests
working.

It seems that there are also some flaky tests.  I am going to address
them later on.

Differential Revision: https://reviews.llvm.org/D58527

llvm-svn: 355320

lldb/packages/Python/lldbsuite/test/functionalities/deleted-executable/TestDeletedExecutable.py

@@ -19,6 +19,7 @@ class TestDeletedExecutable(TestBase):
 
     @skipIfWindows # cannot delete a running executable
     @expectedFailureAll(oslist=["linux"]) # determining the architecture of the process fails
+    @expectedFailureNetBSD
     def test(self):
         self.build()
         exe = self.getBuildArtifact("a.out")